Test circuit and method

ABSTRACT

A method that is disclosed that includes the operations outlined below. Dies are arranged on a test fixture, and each of the dies includes first antennas and at least one via array, wherein the at least one via array is formed between at least two of the first antennas to separate the first antennas. By the first antennas of the dies, test processes are sequentially performed on an under-test device including second antennas that positionally correspond to the first antennas, according to signal transmissions between the first antennas and the second antennas.

RELATED APPLICATIONS

The present application is a divisional application of the U.S.application Ser. No. 14/189,112, filed Feb. 25, 2014, now U.S. Pat. No.9,891,266, issued Feb. 13, 2018, which is herein incorporated byreference.

BACKGROUND

During the manufacturing process of integrated circuits, various testsare performed at one or more stages to ensure that a finished productfunctions adequately. Parts of the tests are performed by feeding signalfrom a test fixture to an under-test device. In operation, theunder-test device is placed to be aligned with the test fixture, and istested by the signals transmitted by the test fixture.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may b e arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1A is a diagram of a top view of a test fixture and an under-testdevice in accordance with various embodiments of the present disclosure.

FIG. 1B is a side view of the test fixture and the under-test device inaccordance with various embodiments of the present disclosure.

FIG. 2A is a partially enlarged view of the test fixture in accordancewith various embodiments of the present disclosure.

FIG. 2B is a simplified top view of the test fixture in accordance withvarious embodiments of the present disclosure.

FIG. 3 is an exemplary diagram of an operation method in accordance withvarious embodiments of the present disclosure.

FIG. 4A is a partially enlarged view of the test fixture in accordancewith various embodiments of the present disclosure.

FIG. 4B is a simplified top view of the test fixture in accordance withvarious embodiments of the present disclosure.

FIG. 5 is a simplified top view of the test fixture in accordance withvarious embodiments of the present disclosure.

FIG. 6 is a simplified top view of the test fixture in accordance withvarious embodiments of the present disclosure.

FIG. 7 is a three-dimensional (3-D) diagram of one of the dies inaccordance with various embodiments of the present disclosure.

FIG. 8 is a three-dimensional diagram of one of the dies in accordancewith various embodiments of the present disclosure.

FIG. 9A, FIG. 9B and FIG. 9C are top vias of one of the dies in the testfixture in accordance with various embodiments of the presentdisclosure.

FIG. 10 is a simplified side view of the test fixture and the under-testdevice in accordance with various embodiments of the present disclosure.

FIG. 11 is an exemplary diagram of an operation method in accordancewith various embodiments of the present disclosure.

FIG. 12 is a simplified side view of the test fixture and the under-testdevice in accordance with various embodiments of the present disclosure.

FIG. 13 is an exemplary diagram of an operation method in accordancewith various embodiments of the present disclosure.

FIG. 14 is a simplified side view of the test fixture and the under-testdevice in accordance with various embodiments of the present disclosure.

FIG. 15 is an exemplary diagram of an operation method in accordancewith various embodiments of the present disclosure.

FIG. 16 is a three-dimensional diagram of test fixture and theunder-test device in accordance with various embodiments of the presentdisclosure.

FIG. 17 is an exemplary diagram of an operation method in accordancewith various embodiments of the present disclosure.

FIG. 18A and FIG. 18B are exemplary diagrams of recorded power peaks inaccordance with various embodiments of the present disclosure.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the invention. Specificexamples of components and arrangements are described below to simplifythe present disclosure. These are, of course, merely examples and arenot intended to be limiting. For example, the formation of a firstfeature over or on a second feature in the description that follows mayinclude embodiments in which the first and second features are formed indirect contact, and may also include embodiments in which additionalfeatures may be formed between the first and second features, such thatthe first and second features may not be in direct contact. In addition,the present disclosure may repeat reference numerals and/or letters inthe various examples. This repetition is for the purpose of simplicityand clarity and does not in itself dictate a relationship between thevarious embodiments and/or configurations discussed.

FIG. 1A is a diagram of a top view of a test fixture 100 and anunder-test device 200 in accordance with various embodiments of thepresent disclosure. FIG. 1B is a side view of the test fixture 100 andthe under-test device 200 in accordance with various embodiments of thepresent disclosure, in which the test fixture 100 is placed above theunder-test device 200.

The test fixture 100 includes a plurality of dies 110. In someembodiments, the dies 110 are formed on a printed circuit board (PCB)115. Each of the dies 110 includes a plurality of antennas 120.

In some embodiments, the under-test device 200 includes a wafer layer215 that includes a plurality of under-test dies 210. Each of theunder-test dies 210 includes a plurality of antennas 220. In furtherembodiments, each of the under-test dies 210 further includes a circuit(not illustrated) that the antennas 220 are formed thereon.

In some embodiments, the dies 110 are arranged in an array andpositionally correspond to the under-test dies 210. Further, each of theantennas 120 positionally corresponds to one of the second antennas 220.

The antennas 120 perform signal transmissions with the antennas 220 toperform test processes. More specifically, the test processes areperformed according to the transmissions of forced signals 130 andfeedback signals between the antennas 120 and the antennas 220.

For illustration with reference to FIG. 1A and FIG. 1B, the antennas 120first transmit the forced signals 130 to the antennas 220. In someembodiments, the test fixture 100 is a wireless probe card that isconnected to a test equipment (not illustrated). The forced signals 130transmitted by the antennas 120 are generated by the test equipment.

In some embodiments, the circuits in the under-test dies 210 generatesthe feedback signals 230 in response to the forced signals 130 receivedby the antennas 220. For illustration, the antennas 120 receive thefeedback signals 230 from the antennas 220.

In some embodiments, the feedback signals 230 are further transmittedfrom the test fixture 100 to the test equipment. The test equipmentdetermines whether the circuits in the under-test dies 210 functionnormally according to the feedback signals 230.

FIG. 2A is a partially enlarged view of the test fixture 100 inaccordance with various embodiments of the present disclosure. Forillustration, the dies 110 labeled as DIE1, DIE2, . . . and DIE12 areillustrated.

In some embodiments, the dies 110 labeled as DIE1, DIE5 and DIE9 aredisposed in one of a plurality of odd columns of the array. The dies 110labeled as DIE2, DIE6 and DIE10 are disposed in one of a plurality ofeven columns of the array. The dies 110 labeled as DIE3, DIE7 and DIE11are disposed in another one of the odd columns of the array. The dies110 labeled as DIE4, DIE8 and DIE12 are disposed in another one of theeven columns of the array.

FIG. 2B is a simplified top view of the test fixture 100 in accordancewith various embodiments of the present disclosure, in which theantennas 120 are not illustrated in FIG. 2B. For illustration, the dies110 are categorized into two die groups GROUP1 and GROUP2.

FIG. 3 is an exemplary diagram of an operation method 300 in accordancewith various embodiments of the present disclosure. In some embodiments,the operation method 300 is applied to the test fixture 100 illustratedin FIG. 2A and FIG. 2B. For illustration, operations of the test fixture100 are described by the operation method 300 with reference to FIG. 2Aand FIG. 2B.

In operation 305, an antenna distance between each of the antennas 120on one of the dies 110 and every one of the antennas 120 of the otherdies 110 is determined.

For illustration, the distance between one of the antennas 120 of thedie labeled as DIE1 and one of the antennas 120 of the die labeled asDIE2 is determined to be D1. The distance between one of antenna 120 ofthe die labeled as DIE1 and one of the antenna 120 of the die labeled asDIE5 is determined to be D2.

In operation 310, the dies 110 are categorized into a plurality of diegroups.

For illustration in FIG. 2B, the dies 110 are categorized into the diegroups GROUP1 and GROUP2. The die group GROUP1 corresponds to the oddcolumns of the array, and the die group GROUP2 corresponds to the evencolumns of the array.

For illustration, the dies 110 in the die group GROUP1 are illustratedas white blocks. The dies 110 in the die group GROUP2 are illustrated aspatterned blocks.

Between each of the antennas 120 of one of the dies 110 in the die groupGROUP1 and every one of the antennas 120 of the other dies 110 in thedie group GROUP1, the antenna distance therebetween is larger than aninterference threshold.

For illustration in FIG. 2A, the dies DIE1, DIE3, DIE5, DIE7, DIE9 andDIE11 are in the die group GROUP1 since they are disposed in two of theodd columns. As a result, the antenna distance between each of theantennas 120 of the die DIE1 and every one of the antennas 120 of theother dies, e.g., DIE5, DIE9, DIE3, DIE7 and DIE11, is larger than theinterference threshold.

Similarly, between each of the antennas 120 of one of the dies 110 inthe die group GROUP2 and every one of the antennas 120 of the other dies110 in the die group GROUP2, the antenna distance therebetween is largerthan an interference threshold.

For illustration in FIG. 2A, the dies DIE2, DIE4, DIE6, DIE8, DIE10 andDIE12 are in the die group GROUP2 since they are disposed in two of theeven columns. As a result, the antenna distance between each of theantennas 120 of the die DIE2 and every one of the antennas 120 of theother dies, e.g. DIE6, DIE10, DIE4, DIE8 and DIE12, is larger than theinterference threshold.

On the other hand, when the antenna distance between any two of theantennas 120 from two of the dies 110 is smaller than the interferencethreshold, the two dies 110 are not categorized in the same die group.For example, the antenna distance of some pairs of the antennas 120 fromboth of the dies DIE1 and DIE2 is smaller than the interferencethreshold. As a result, the dies DIE1 and DIE2 are not categorized inthe same die group.

In some embodiments, the interference threshold is in a range of five toten times of the wavelength of the signals transmitted by the antennas120 and 220. For example, if the wavelength of the signals transmittedby the antennas 120 and 220 is 100 micrometers, the interferencethreshold is within a range from about 500 micrometers to 1000micrometers. When the antenna distance between two of the antennas 120is larger than the interference threshold, the interference generatedtherebetween is decreased.

In operation 315, a plurality of test processes are sequentiallyperformed on the under-test device 200 by the antennas 120 of the dies110 of the die groups GROUP1 and GROUP2. Each of the test processes isperformed according to signal transmissions between the antennas 120 andthe second antennas 220.

In some embodiments, the test process corresponding to the die groupGROUP1 is performed first, and the test process corresponding to the diegroup GROUP2 is performed subsequently. In some embodiments, the testprocess corresponding to the die group GROUP2 is performed first, andthe test process corresponding to the die group GROUP1 is performedsubsequently.

Based on the operations, the test fixture 100 performs the testprocesses sequentially to avoid the interference between thegeometrically crowded antennas 120. As a result, even the under-testdies 210 and the dies 110 are manufactured with a high density, theinterference of the antennas 120 between the dies is prevented. In someembodiments, the distance between each of two of the adjacent under-testdies 210 or each two of the adjacent dies 110 equals to the width of thescribe line formed therebetween. In some embodiments, the scribe line iswithin a range from about 80 micrometers to about 200 micrometers.

FIG. 4A is a partially enlarged view of the test fixture 100 inaccordance with various embodiments of the present disclosure. Forillustration in FIG. 4A, the dies 110 labeled as DIE1, DIE2, . . . andDIE12 are illustrated.

In some embodiments, the dies 110 labeled as DIE1, DIE3, DIE9 and DIE11are disposed in an intersection of one of the odd columns and one of theodd rows of the array respectively. The dies 110 labeled as DIE6 andDIE8 are disposed in an intersection of one of the even columns and oneof the even rows of the array respectively. The dies 110 labeled asDIE2, DIE4, DIE10 and DIE12 are disposed in one of the even columns andone of the odd rows of the array respectively. The dies 110 labeled asDIE5 and DIE7 are disposed in one of the odd columns and one of the evenrows of the array respectively.

FIG. 4B is a simplified top view of the test fixture 100 in accordancewith various embodiments of the present disclosure, in which theantennas 120 are not illustrated in FIG. 4B. For illustration, the dies110 are categorized into two die groups GROUP1 and GROUP2.

The die group GROUP1 corresponds to the dies 110 each located at theintersection of one of the odd columns and one of the odd rows of thearray, and the dies 110 each located at the intersection of one of theeven columns and one of the even rows of the array. The die group GROUP2corresponds to the dies 110 each located at the intersection of one ofthe even columns and one of the odd rows of the array, and the dies 110each located at the intersection of one of the odd columns and one ofthe even rows of the array.

Though the density of the antennas 120 is higher than that of theantennas 120 illustrated in FIG. 2A, the antenna distance between eachtwo of the antennas 120 of two obliquely adjacent dies 110 is stilllarger than the interference threshold. As a result, the dies 110 in thedie groups GROUP1 and GROUP2 alternate to each other to form a chequeredpattern. The test processes are performed sequentially by the die groupsGROUP1 and GROUP2 to prevent the interference.

FIG. 5 is a simplified top view of the test fixture 100 in accordancewith various embodiments of the present disclosure, in which theantennas 120 are not illustrated in FIG. 5.

For illustration in FIG. 5, the dies 110 are covered by a plurality of2×2 windows illustrated by thick lines. Each of the 2×2 windows includesat most four of the dies 110. The dies 110 are categorized into four diegroups GROUP1, GROUP2, GROUP3 and GROUP4. Each of the four die groupsGROUP1-GROUP4 includes one of the dies 110 in each of the 2×2 windowsthat are in the same position of the 2×2 windows.

Under such a condition, between each of the antennas 120 of one of thedies 110 in one of the die groups and every one of the antennas 120 ofthe other dies 110 in the same die groups, the antenna distance isguaranteed to be larger than the interference threshold. Since each ofthe test processes is not performed by any two of the adjacent antennas,the condition of severe interference of the antennas is avoided.

FIG. 6 is a simplified top view of the test fixture 100 in accordancewith various embodiments of the present disclosure, in which theantennas 120 are not illustrated in FIG. 6.

For illustration in FIG. 6, the dies 110 are covered by a plurality of3×3 windows illustrated by thick lines. Each of the 3×3 windows includesat most nine of the dies 110. The dies 110 are further categorized intonine die groups GROUP1, GROUP2, GROUP3, GROUP4, GROUP5, GROUP6, GROUP7,GROUP8 and GROUP9. Each of the nine die groups GROUP1-GROUP9 includesone of the dies 110 in each of the 3×3 windows that are in the sameposition of the 3×3 windows.

Under such a condition, between each of the antennas 120 of one of thedies 110 in one of the die groups and every one of the antennas 120 ofthe other dies 110 in the same die groups, the antenna distance isguaranteed to be larger than the interference threshold. Since each ofthe test processes is not performed by any two of the adjacent antennas,the condition of severe interference of the antennas is avoided.

FIG. 7 is a three-dimensional (3-D) diagram of one of the dies 110 inaccordance with various embodiments of the present disclosure.

For illustration, the die 110 includes four antennas 120 and a via array700. The via array 700 separates two of the antennas 120 from the othertwo of the antennas 120. In some embodiments, the via array 700 includesa plurality of vias 710. In some embodiments, the via array 700 furtherincludes at least one shielding plane 720 stretching to connect the vias710. For illustration in FIG. 7, the via array 700 includes threeshielding planes 720.

In some embodiments, the via array 700 includes an electric-shieldingmaterial. In some embodiments, the electric-shielding material is metal.In further embodiments, the material of the via array 700 is copper.

In some approaches, when the antenna distance between the antennas 120in a single die 110 is small, the interference between the antennas 120occurs.

Compared to the preceding approaches, in the present disclosure, the viaarray 700 is disposed to provide a one-dimensional shielding effect. Theinterference between the antennas 120 in one side of the via array 700and the other side of the via array 700 is prevented.

FIG. 8 is a three-dimensional diagram of one of the dies 110 inaccordance with various embodiments of the present disclosure.

For illustration, the die 110 includes three antennas 120 and a viaarray 800. The via array 800 includes a plurality of vias 810. Moreover,the via array 800 is formed to surround one of the antennas 120.

As a result, the via array 800 provides a two-dimensional shieldingeffect to prevent the surrounded antenna 120 from interference. Theinterference from the environment that the surrounded antenna 120locates is prevented by the via array 800.

FIG. 9A, FIG. 9B and FIG. 9C are top vias of one of the dies 110 in thetest fixture 100 in accordance with various embodiments of the presentdisclosure.

For illustration, the die 110 illustrated in FIG. 9A, FIG. 9B and FIG.9C includes two antennas 120 and a via array 900. The via array 900includes a plurality of vias 910. Moreover, the via array 900 is formedto separate the two antennas 120.

In some embodiments, each of the vias 910 and a correspondingsurrounding region 920 form a via cell 930. In some embodiments, each ofthe via cells 930 is a square shape, as illustrated in FIG. 9A. In someembodiments, each of the via cells 930 is a hexagonal shape, asillustrated in FIG. 9B. In some embodiments, each of the via cells 930is a rhombic shape, as illustrated in FIG. 9C.

Based on different shapes of the via cells 930, different arrangementsand densities of the via array 900 are accomplished. As a result,different interference conditions of the antennas 120 are addressed byusing different shapes of the via cells 930. In some embodiments, theshapes of the via cells illustrated in FIG. 9A, FIG. 9B and FIG. 9C areapplied to the vias 810 of the via array 800. More specifically,different shapes of the via cells are used in the via array 800 tosurround the antenna 120.

FIG. 10 is a simplified side view of the test fixture 100 and theunder-test device 200 in accordance with various embodiments of thepresent disclosure, in which the test fixture 100 is placed above theunder-test device 200.

For illustration, the test fixture 100 includes a plurality of antennas120 labeled as A11, A12 and A13. In some embodiments, the antennas 120are formed on a planar surface of the test fixture 100.

The under-test device 200 includes the wafer layer 215. Forillustration, the wafer layer 215 includes a plurality of antennas 220labeled as A21, A22 and A23.

For illustration, the distance between the antenna 220 labeled as A21and the antenna 120 labeled as A11 is D11. The distance between theantenna 220 labeled as A22 and the antenna 120 labeled as A12 is D12.The distance between the antenna 220 labeled as A23 and the antenna 120labeled as A13 is D13.

FIG. 11 is an exemplary diagram of an operation method 1100 inaccordance with various embodiments of the present disclosure. In someembodiments, the operation method 1100 is applied to the test fixture100 illustrated in FIG. 10. For illustration, operations of the testfixture 100 are described by the operation method 1100 with reference toFIG. 10.

In operation 1105, forced signals 150A, 150B and 150C are transmittedfrom the antennas 120 of the test fixture 100 to the antennas 220 of thewafer layer 215.

For illustration, the forced signal 150A is transmitted from the antenna120 labeled as A11 to the antenna 220 labeled as A21. The forced signal150B is transmitted from the antenna 120 labeled as A12 to the antenna220 labeled as A22. The forced signal 150C is transmitted from theantenna 120 labeled as A13 to the antenna 220 labeled as A23.

In operation 1110, feedback signals 250A, 250B and 250C are receivedfrom the antennas 220 by the antennas 120.

For illustration, the feedback signal 250A is received from the antenna220 labeled as A21 by the antenna 120 labeled as A11. The feedbacksignal 250B is received from the antenna 220 labeled as A22 by theantenna 120 labeled as A12. The feedback signal 250C is received fromthe antenna 220 labeled as A23 by the antenna 120 labeled as A13.

In operation 1115, a surface warping condition of the wafer layer 215 isdetermined according to a received power of each of the feedback signals250A, 250B and 250C.

For illustration, when the received power of the feedback signal 250B islarger than that of the feedback signal 250A, the distance D12 isdetermined to be shorter than the distance D11. Similarly, when thereceived power of the feedback signal 250B is larger than that of thefeedback signal 250C, the distance D12 is determined to be shorter thanthe distance D13.

As a result, the distance D12 corresponding to the antenna 220 labeledas A22 is determined to be shorter than the distances D11 and D13corresponding to the antennas 220 labeled as A21 and A23. The surfacewarping condition of the wafer layer 215 is determined to be a “cry”case. Explained in a different way, the two sides of the wafer layer 215are bent away from the test fixture 100.

In some embodiments, different surface warping conditions are determinedaccording to different combinations of the received power of thefeedback signals. A “smile” case is determined when the distance D12 isdetermined to be longer than the distances D11 and D13. Explained in adifferent way, the two sides of the wafer layer 215 are bent toward thetest fixture 100. Moreover, a planar case is determined when thedistance D12 is determined to equal to the distances D11 and D13.

FIG. 12 is a simplified side view of the test fixture 100 and theunder-test device 200 in accordance with various embodiments of thepresent disclosure, in which the test fixture 100 is placed above theunder-test device 200.

The test fixture 100 and the under-test device 200 substantially includethe same components as those of the test fixture 100 and the under-testdevice 200 illustrated in FIG. 10. Compared with the under-test device200 illustrated in FIG. 10, the antennas 220 labeled as A21 and A23 areformed inside of the wafer layer 215. Moreover, the under-test device200 illustrated in FIG. 12 further includes an antennas 220 labeled asA24.

For illustration, the antennas 220 labeled as A21 and A23 aresymmetrically distributed to surround the antennas 220 labeled as A22and A24. For illustration, the distance between the antenna 220 labeledas A21 and the antenna 220 labeled as A22 is D21. The distance betweenthe antenna 220 labeled as A21 and the antenna 220 labeled as A24 isD22. The distance between the antenna 220 labeled as A23 and the antenna220 labeled as A22 is D23. The distance between the antenna 220 labeledas A23 and the antenna 220 labeled as A24 is D24.

FIG. 13 is an exemplary diagram of an operation method 1300 inaccordance with various embodiments of the present disclosure. In someembodiments, the operation method 1300 is applied to the test fixture100 illustrated in FIG. 12. For illustration, operations of the testfixture 100 are described by the operation method 1300 with reference toFIG. 12.

In operation 1305, forced signals 160A and 160B are transmitted from theantennas 120 of the test fixture 100 to the antennas 220 of the waferlayer 215.

For illustration, the forced signal 160A is transmitted from the antenna120 labeled as A11 to the antenna 220 labeled as A21. The forced signal160B is transmitted from the antenna 120 labeled as A13 to the antenna220 labeled as A23.

In operation 1310, the antennas 220 labeled as A21 and A23 are activatedto perform signal transmissions with the antennas 220 labeled as A22 andA24.

In operation 1315, feedback signals 260A and 270A are received by theantennas 120 labeled as A11 from the antennas 220 labeled as A22 and A24through the antenna 220 labeled as A21. Feedback signals 260B and 270Bare received by the antennas 120 labeled as A13 from the antennas 220labeled as A22 and A24 through the antenna 220 labeled as A23.

In operation 1320, a physical warping condition of the wafer layer 215is determined according to a received power of each of the feedbacksignals 260A, 260B, 270A and 270B.

For illustration, when the received power of the feedback signal 270A islarger than that of the feedback signal 260A, the distance D22 isdetermined to be shorter than the distance D21. Similarly, when thereceived power of the feedback signal 270B is larger than that of thefeedback signal 260B, the distance D24 is determined to be shorter thanthe distance D23.

As a result, the physical warping condition of the wafer layer 215 isdetermined to be a “cry” case. Explained in a different way, the twosides of the wafer layer 215 are bent away from the test fixture 100.

In some embodiments, different physical warping conditions aredetermined according to different combinations of the received power ofthe feedback signals. A “smile” case is determined when the distancesD21 and D23 are determined to be longer than the distances D22 and D24respectively. Explained in a different way, the two sides of the waferlayer 215 are bent toward the test fixture 100. Moreover, a planar caseis determined when the distances D21 and D23 are determined to equal tothe distances D22 and D24 respectively.

FIG. 14 is a simplified side view of the test fixture 100 and theunder-test device 200 in accordance with various embodiments of thepresent disclosure, in which the test fixture 100 is placed above theunder-test device 200.

The test fixture 100 substantially includes the same components as thoseof the test fixture 100 illustrated in FIG. 10.

In some embodiments, the under-test device 200 is a three-dimensionalintegrated circuit. The under-test device 200 includes two wafer layers215 and 225.

For illustration, the wafer layer 215 includes a plurality of antennas220 labeled as A21, A22 and A23. The antennas 220 labeled as A21, A22and A23 are formed in the surface of the wafer layer 215 opposite to thetest fixture 100.

For illustration, the wafer layer 225 includes a plurality of antennas320 labeled as A31, A32 and A33. For illustration, the distance betweenthe antenna 320 labeled as A31 and the antenna 220 labeled as A21 isD31. The distance between the antenna 320 labeled as A32 and the antenna220 labeled as A22 is D32. The distance between the antenna 320 labeledas A33 and the antenna 220 labeled as A23 is D33.

FIG. 15 is an exemplary diagram of an operation method 1500 inaccordance with various embodiments of the present disclosure. In someembodiments, the operation method 1500 is applied to the test fixture100 illustrated in FIG. 14. For illustration, operations of the testfixture 100 are described by the operation method 1300 with reference toFIG. 14.

In operation 1505, forced signals 180A, 180B and 180C are transmittedfrom the antennas 120 of the test fixture 100 to the antennas 220 of thewafer layer 215.

For illustration, the forced signal 180A is transmitted from the antenna120 labeled as A11 to the antenna 220 labeled as A21. The forced signal180B is transmitted from the antenna 120 labeled as A12 to the antenna220 labeled as A22. The forced signal 180C is transmitted from theantenna 120 labeled as A13 to the antenna 220 labeled as A23.

In operation 1510, the antennas 220 labeled as A21, A22 and A23 areactivated to perform signal transmissions with the antennas 320.

For illustration, the antennas 220 labeled as A21 performs signaltransmission with the antenna 320 labeled as A31. The antennas 220labeled as A22 performs signal transmission with the antenna 320 labeledas A32. The antennas 220 labeled as A23 performs signal transmissionwith the antenna 320 labeled as A33.

As a result, each two of the corresponding antennas in the wafer layers215 and 225 forms a signal transmission chain.

In operation 1515, feedback signals 280A, 280B and 280C are received bythe antennas 120 from the antennas 320 through the antennas 220.Explained in a different way, each of the feedback signals 280A, 280Band 280C is received by the antennas through the corresponding signaltransmission chain.

For illustration, the feedback signal 280A is received by the antennas120 labeled as A11 from the antennas 320 labeled as A31 through theantennas 220 labeled as A21. The feedback signal 280B is received by theantennas 120 labeled as A12 from the antennas 320 labeled as A32 throughthe antennas 220 labeled as A22. The feedback signal 280C is received bythe antennas 120 labeled as A13 from the antennas 320 labeled as A33through the antennas 220 labeled as A23.

In operation 1520, a surface warping condition of the wafer layer 225 isdetermined according to a received power of each of the feedback signals280A, 280B and 280C.

For example, when the received power of the feedback signal 280B islarger than that of the feedback signal 280A, the distance D32 isdetermined to be shorter than the distance D31. Similarly, when thereceived power of the feedback signal 280B is larger than that of thefeedback signal 280C, the distance D32 is determined to be shorter thanthe distance D33.

As a result, in the three-dimensional circuit, the correspondingantennas in different wafer layers form signal transmission chains. Byforcing the forced signal, the signal transmission chains are activated.The feedback signals are received from the under-test layer through thesignal transmission chains. The surface warping condition of the waferlayers under a top wafer layer is determined.

In some embodiments, the operations illustrated in FIG. 11, FIG. 13 andFIG. 15 are performed sequentially. For example, when the surfacewarping condition of the wafer layer 215 is determined to be planar, thephysical warping condition of the wafer layer 215 is determinedsubsequently. Moreover, when the physical warping condition of the waferlayer 215 is determined to be planar, the surface warping condition ofthe wafer layer 225 is determined subsequently.

FIG. 16 is a three-dimensional diagram of test fixture 100 and theunder-test device 200 in accordance with various embodiments of thepresent disclosure, in which the test fixture 100 is placed above theunder-test device 200.

The test fixture 100 substantially includes the same components as thoseof the test fixture 100 illustrated in FIG. 10, in which only oneantenna 120 is exemplary illustrated in FIG. 16. For illustration, theprojection of the antenna 120 on the under-test device 200 serves as anorigin and has a coordinate of (0,0).

The under-test device 200 substantially includes the same components asthose of the under-test device 200 illustrated in FIG. 10. Compared withthe under-test device 200 illustrated in FIG. 10, the antennas 220 arearranged to have the coordinates of (X1, Y1), (X2, Y2) and (X3, Y3)relative to the origin respectively.

FIG. 17 is an exemplary diagram of an operation method 1700 inaccordance with various embodiments of the present disclosure. In someembodiments, the operation method 1700 is applied to the test fixture100 illustrated in FIG. 16. For illustration, operations of the testfixture 100 are described by the operation method 1700 with reference toFIG. 16.

In operation 1705, the test fixture 100 is moved along a direction X anda direction Y to perform signal transmissions between the antenna 120and the antennas 220.

In operation 1710, whether a power peak is found is determined.Operation 1710 is explained with reference to FIG. 18A and FIG. 18Billustrated below.

FIG. 18A and FIG. 18B are exemplary diagrams of recorded power peaks P1,P2, P3 and P4 in accordance with various embodiments of the presentdisclosure.

For illustration in FIG. 18A, when the test fixture 100 is moved alongthe Y direction, two power peaks P1 and P2 that correspond to theantennas 220 are found. In some embodiments, the power peaks P1 and P2correspond to the antennas 220 having the coordinates (X1, Y1) and (X2,Y2) respectively.

For illustration in FIG. 18B, when the test fixture 100 is moved alongthe X direction, two power peaks P3 and P4 that correspond to theantennas 220 are found. In some embodiments, the power peaks P3 and P4correspond to the antennas 220 having the coordinates (X2, Y2) and (X3,Y3) respectively.

As a result, when the power peak P1, P2, P3 or P4 is found, the powerpeak and a corresponding position are recorded in operation 1715. Sincethe test fixture 100 moves relative to the origin (0,0), thecorresponding positions of the power peaks are recorded by using acoordinate system. In some embodiments, the coordinate system is definedby the origin, the X direction and the Y direction, in which the Xdirection is a first axis and the Y direction is a second axis.

On the other hand, when the power peak P1, P2, P3 or P4 is not foundyet, the flow goes back to operation 1705 to continuously move the testfixture 100.

In operation 1720, whether the power peaks P1-P4 correspond to all theantennas 220 are recorded is determined.

When the power peaks P1-P4 are not completely recorded, the flow goesback to operation 1705 to continuously move the test fixture 100.

When all the power peaks P1-P4 are recorded, the coordinates (X1, Y1),(X2, Y2) and (X3, Y3) of the antennas 220 are obtained.

The position of the antenna 120 is calibrated to aim one of the antennas220 according to the peak power positions in operation 1725. Forexample, the antenna 120 is calibrated to aim the antenna 220corresponding to the coordinate (X2, Y2).

Based on the operations in FIG. 17, the power peaks of the signaltransmissions between the antenna 120 and the antennas 220 aredetermined. The position of the antenna 120 is calibrated according tothe power peaks to aim one of the antennas 220. The distance between theantenna 120 and the aimed antenna 220 is minimized such that the powerof the signals transmissions performed therebetween is maximized. Theefficiency of the test process performed by the signal transmissionsbetween the antenna 120 and the aimed antenna 220 is increased.

In some embodiments, a method is disclosed that includes the operationsoutlined below. For a plurality of dies on a test fixture, wherein eachof the dies includes a plurality of first antennas, an antenna distancebetween each of the first antennas in one of the dies and every one ofthe first antennas of the other dies is determined, wherein the dies arearranged in an array and positionally correspond to a plurality ofunder-test dies of an under-test device. The dies are categorized into aplurality of die groups, wherein the antenna distance between each ofthe first antennas in one of the dies in one of the die groups and everyone of the first antennas of the other dies in the same one of the diegroups is larger than an interference threshold. A plurality of testprocesses are sequentially performed on the under-test device by thefirst antennas of the dies in the die groups, and each of the testprocesses is performed according to signal transmissions between thefirst antennas and a plurality of second antennas of the under-testdevice, wherein each of the second antennas positionally corresponds toone of the first antennas.

Also disclosed is a method that is disclosed that includes theoperations outlined below. Dies are arranged on a test fixture, and eachof the dies includes first antennas and at least one via array, whereinthe at least one via array is formed between at least two of the firstantennas to separate the first antennas. By the first antennas of thedies, test processes are sequentially performed on an under-test deviceincluding second antennas that positionally correspond to the firstantennas, according to signal transmissions between the first antennasand the second antennas.

Also disclosed is a method that is disclosed that includes theoperations outlined below. By first antennas of dies on a test fixture,test processes are sequentially performed on an under-test deviceincluding second antennas that positionally correspond to the firstantennas, according to signal transmissions between the first antennasand the second antennas. An antenna distance between each of the firstantennas of one of the dies in one of die groups and every one of thefirst antennas of the other dies in the same one of the die groups islarger than an interference threshold.

In this document, the term “connected” may be termed as “electricallyconnected”, and the term “coupled” may be termed as “electricallycoupled”. “Connected” and “coupled” may also be used to indicate thattwo or more elements cooperate or interact with each other.

The number and configuration of the dies, the under-test dies, the diegroups and the antennas therein in this document are for illustrativepurposes. Various numbers and configurations of the dies, the under-testdies, the die groups and the antennas therein are within thecontemplated scope of the present disclosure.

The number and configuration of the via arrays, the vias and theshielding planes therein in this document is for illustrative purposes.Various numbers and configurations of the via arrays, the vias and theshielding planes therein are within the contemplated scope of thepresent disclosure.

The number and configuration of the wafer layers in the under-testdevice therein in this document are for illustrative purposes. Variousnumbers and configurations of wafer layers therein are within thecontemplated scope of the present disclosure.

The number and configuration of the signal-forcing probe, thesignal-forcing path, the signal-sensing path and the signal-receivingpad therein in this document are for illustrative purposes. Variousnumbers and configurations of the contact probes and the monitoringprobes therein are within the contemplated scope of the presentdisclosure.

The above illustrations include exemplary operations, but the operationsare not necessarily performed in the order shown. Operations may beadded, replaced, changed order, and/or eliminated as appropriate, inaccordance with the spirit and scope of various embodiments of thepresent disclosure.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A method, comprising: for a plurality of dies ona test fixture, wherein each of the dies includes a plurality of firstantennas, determining an antenna distance between each of the firstantennas of one of the dies and every one of the first antennas of theother dies, wherein the dies are arranged in an array and positionallycorrespond to a plurality of under-test dies of an under-test device;categorizing the dies into a plurality of die groups according to theantenna distances between the first antennas in each die, wherein theantenna distance between each of the first antennas of one of the diesin one of the die groups and every one of the first antennas of theother dies in the same one of the die groups is larger than aninterference threshold; and sequentially performing a plurality of testprocesses on the under-test device by the first antennas of the dies inthe die groups, wherein each of the test processes is performedaccording to signal transmissions between the first antennas and aplurality of second antennas of the under-test device, wherein each ofthe second antennas positionally corresponds to one of the firstantennas.
 2. The method of claim 1, wherein categorizing the diescomprises: categorizing the dies into a first die group comprising aplurality of odd columns/rows of the dies and a second die groupcomprising a plurality of even columns/rows of the dies.
 3. The methodof claim 1, wherein categorizing the dies comprises: categorizing thedies into a first die group and a second die group, wherein the dies inthe first die group and the dies in the second die group alternate toeach other to form a chequered pattern.
 4. The method of claim 1,wherein the dies are covered by a plurality of 2×2 windows eachcomprising at most four of the dies, and categorizing the diescomprises: categorizing the dies into four die groups, wherein each ofthe four die groups comprises one of the dies in each of the 2×2 windowsthat are in a same position of the 2×2 windows.
 5. The method of claim1, wherein the dies are covered by a plurality of 3×3 windows eachcomprising at most nine of the dies, and categorizing the diescomprises: categorizing the dies into nine die groups, wherein each ofthe nine die groups comprises one of the dies in each of the 3×3 windowsthat are in a same position of the 3×3 windows.
 6. The method of claim1, further comprising: performing a single test process on the dies whenthe antenna distance between each of the first antennas of one of thedies and each of the first antennas of the other dies is larger than theinterference threshold, wherein the single test process is performedaccording to the signal transmissions between the first antennas and thesecond antennas of the under-test device.
 7. The method of claim 1,wherein a range of the interference threshold is five to ten times of awavelength of signals transmitted by the first antennas and the secondantennas.
 8. The method of claim 1, wherein a distance between each twoof adjacent dies equals to a width of a scribe line formed therebetween.9. A method comprising: by first antennas of dies on a test fixture,sequentially performing test processes on an under-test devicecomprising second antennas that positionally correspond to the firstantennas, according to signal transmissions between the first antennasand the second antennas, wherein performing the test processescomprises: transmitting first forced signals from the first antennas tothe second antennas; by the first antennas, receiving first feedbacksignals from the second antennas; and determining a first surfacewarping condition of the under-test device according to a first receivedpower of each of the first feedback signals, wherein an antenna distancebetween each of the first antennas of one of the dies in one of diegroups and every one of the first antennas of the other dies in the sameone of the die groups is larger than an interference threshold, whereinthe under-test device further comprises third antennas that positionallycorrespond to the second antennas, and the method further comprises:transmitting second forced signals from the first antennas to activatethe second antennas to perform signal transmissions with the thirdantennas; by the first antennas, receiving second feedback signals fromthe third antennas through the second antennas; and determining a secondsurface warping condition of the under-test device according to a secondreceived power of each of the second feedback signals.
 10. The method ofclaim 9, further comprising: categorizing the dies that are covered by aplurality of N×N windows, into die groups, wherein each of the diegroups comprises one of the dies in each of N×N windows that are in asame position of the N×N windows, wherein N is a positive integer. 11.The method of claim 1, wherein: a first die is adjacent a second die ina first direction, a first antenna of the first die that is nearest thesecond die and a first antenna of the second die that is nearest thefirst die is separated by a first distance that is less than theinterference threshold, the first die is adjacent a third die in asecond direction different than the first direction, and a first antennaof the first die that is nearest the third die and a first antenna ofthe third die that is nearest the first die is separated by a seconddistance that is greater than the interference threshold.
 12. The methodof claim 10, wherein a range of the interference threshold is five toten times of a wavelength of the first forced signals transmitted fromthe first antennas.
 13. The method of claim 9, further comprising:categorizing the dies into a first die group comprising a plurality ofodd columns/rows of the dies and a second die group comprising aplurality of even columns/rows of the dies.
 14. The method of claim 9,further comprising: categorizing the dies into a first die group and asecond die group, wherein the dies in the first die group and the diesin the second die group alternate to each other to form a chequeredpattern.
 15. The method of claim 9, wherein: the dies are covered by aplurality of 2×2 windows each comprising at most four of the dies, andthe method further comprises categorizing the dies into four die groups,wherein each of the four die groups comprises one of the dies in each ofthe 2×2 windows that are in a same position of the 2×2 windows.
 16. Themethod of claim 9, wherein: the dies are covered by a plurality of 3×3windows each comprising at most nine of the dies, and the method furthercomprises categorizing the dies into nine die groups, wherein each ofthe nine die groups comprises one of the dies in each of the 3×3 windowsthat are in a same position of the 3×3 windows.
 17. The method of claim9, wherein a range of the interference threshold is five to ten times ofa wavelength of the first forced signals transmitted from the firstantennas.
 18. The method of claim 9, wherein a range of the interferencethreshold is five to ten times of a wavelength of the first feedbacksignals received from the second antennas.
 19. The method of claim 18,wherein the range of the interference threshold is five to ten times ofa wavelength of the first forced signals transmitted from the firstantennas.
 20. The method of claim 9, wherein a distance between twoadjacent dies of the dies on the test fixture is equal to a width of ascribe line formed therebetween.